NEW YORK (Reuters) - The U.S. Federal
Bureau of Investigation and the Securities and Exchange Commission are
investigating possible insider trading involving billionaire investor
Carl Icahn, golfer Phil Mickelson and Las Vegas gambler William Walters,
a source familiar with the matter said.

Federal investigators are looking into whether Mickelson and
Walters may have traded illegally on private information provided by
Icahn about his investments in public corporations, the source told
Reuters, confirming a report by the Wall Street Journal on Friday.

Icahn, Mickelson and Walters were not immediately available for
comment. Spokespeople for the FBI and SEC declined to comment.

The investigation is the latest case to emerge from a multi-year
crackdown on insider trading by U.S. authorities. It involves two of
the highest-profile personalities in finance and sport: famously
combative activist investor Icahn and multiple Masters champion
Mickelson.

Walters, who plays golf with Mickelson, is a well-known sports
bettor who met Icahn through a mutual acquaintance and struck up a
friendship, according to the Journal.

The investigation into the trio centers on suspicious trades in
Clorox Co options days before Icahn announced a bid to acquire the
company in 2011, according to the Journal, citing people briefed on
the probe.

Icahn had accumulated a 9.1 percent stake in Clorox in February
2011. In July, the activist investor made an offer for the company
that valued it at above $10 billion and sent its stock soaring.